telephone circuit

[lerameur]

Hello,

I am using a pic controller for a dialer project. My goal is to dial
a number, when the receiving end picks up, then send some dtmf tone
for a few minutes.
Sounds simple, but I do not know how to tell my controller that the
receiving end has picked up or not. Right now I just let it ring for
10 seconds, and send my dial tone after that. I would like it to be
more 'intelligent' by knowing when the receiver has picked up so I can
send the dial tone (message),
thanks

K

 

[John Fields]

On Tue, 2 Sep 2008 12:16:36 -0700 (PDT), lerameur <lerameur@yahoo.com>
wrote:

Hello,

I am using a pic controller for a dialer project. My goal is to dial
a number, when the receiving end picks up, then send some dtmf tone
for a few minutes.
Sounds simple, but I do not know how to tell my controller that the
receiving end has picked up or not. Right now I just let it ring for
10 seconds, and send my dial tone after that. I would like it to be
more 'intelligent' by knowing when the receiver has picked up so I can
send the dial tone (message),
thanks

---
If you're going to use the remote phone for remote control purposes
you could have it shake hands with the controller:

LOCAL REMOTE

DIAL---------------------------->DETECT RING
WAIT FOR HANDSHAKE GO OFF-HOOK
RX HANDSHAKE <------------------ TX DTMF HANDSHAKE TONES
WAIT FOR DTMF DATA
TX DTMF DATA-------------------->RX DTMF DATA

JF

 

[lerameur]

On Sep 2, 5:15 pm, John Fields <jfie...@austininstruments.com> wrote:

On Tue, 2 Sep 2008 12:16:36 -0700 (PDT), lerameur <leram...@yahoo.com
wrote:

Hello,

I am using a pic controller  for a dialer project. My goal is to dial
a number, when the receiving end picks up, then send some dtmf tone
for a few minutes.
Sounds simple, but I do not know how to tell my controller that the
receiving end has picked up or not. Right now I just let it ring for
10 seconds, and send my dial tone after that. I would like it to be
more 'intelligent' by knowing when the receiver has picked up so I can
send the dial tone (message),
thanks

---
If you're going to use the remote phone for remote control purposes
you could have it shake hands with the controller:

      LOCAL                           REMOTE

DIAL---------------------------->DETECT RING
WAIT FOR HANDSHAKE               GO OFF-HOOK
RX HANDSHAKE <------------------ TX DTMF HANDSHAKE TONES
                                 WAIT FOR DTMF DATA
TX DTMF DATA-------------------->RX DTMF DATA

JF

Yes but how is this handle in circuitry. I just realize that I cannot
use the same circuit with audio transformer as I did in DTMF to signal
out. How should the voltage at the line while dialing? and once the
party has pick up the phone ?

Ken

 

[Stephen J. Rush]

On Tue, 02 Sep 2008 12:16:36 -0700, lerameur wrote:

Hello,

I am using a pic controller for a dialer project. My goal is to dial a
number, when the receiving end picks up, then send some dtmf tone for a
few minutes.
Sounds simple, but I do not know how to tell my controller that the
receiving end has picked up or not. Right now I just let it ring for 10
seconds, and send my dial tone after that. I would like it to be more
'intelligent' by knowing when the receiver has picked up so I can send
the dial tone (message),

When the central office connects to the called phone, it sends the 20-Hz
100-volt ring signal to that phone and a tone-burst signal called the
ringback to you. When someone making a call says he "hears it ringing",
he's referring to the ringback. I don't remember offhand the two
frequencies involved, but a little Googling will find them. Send the
DTMF dial string, then wait for the ringback. Measure the time between
tone bursts, because it may vary between central offices. If that much
time elapses without a ringback burst, you know the other end has gone
off-hook. To be safe, you also need to detect the error conditions: a
busy signal or complex audio that doesn't sound like the ringback or busy
tones. That will be one of the call-not-completed voice messages.

 

[Jasen Betts]

On 2008-09-02, lerameur <lerameur@yahoo.com> wrote:

Hello,

I am using a pic controller for a dialer project. My goal is to dial
a number, when the receiving end picks up, then send some dtmf tone
for a few minutes.
Sounds simple, but I do not know how to tell my controller that the
receiving end has picked up or not. Right now I just let it ring for
10 seconds, and send my dial tone after that. I would like it to be
more 'intelligent' by knowing when the receiver has picked up so I can
send the dial tone (message),
thanks

some exchanges will signal when the remote end picks up (and when they
hang up) by reversing the polarity. if you don't have that you have to
do what modems do and listen for a signal from the remote end.
or do what fax machines do and send a tone periodically uitil you get
a reply.

Bye.
Jasen

 

[John Mianowski]

On Sep 2, 2:16 pm, lerameur <leram...@yahoo.com> wrote:

Hello,

I am using a pic controller  for a dialer project. My goal is to dial
a number, when the receiving end picks up, then send some dtmf tone
for a few minutes.
Sounds simple, but I do not know how to tell my controller that the
receiving end has picked up or not. Right now I just let it ring for
10 seconds, and send my dial tone after that. I would like it to be
more 'intelligent' by knowing when the receiver has picked up so I can
send the dial tone (message),
thanks

K

That's always a problem for loop-start lines, which I presume is what
you have. They're designed for calls placed by humans, to humans,
rather than machine-to-machine trunks. There isn't any 100% positive
electrical signal, such as a voltage level, current flow, etc. that's
transmitted end-to-end & can alert a dumb machine to a distant-end
answer.

What's usually used to determine answer is call progress tone
detection. Call progress tones are the various tones that alert a
human caller to the status of the call. Common call progress tones
include dial tone, ring-back, busy, & reorder. All of these tones
appear within the audio frequency band of the circuit, mostly as pairs
of frequencies. If you've ever called to or from certain PBXes, or
various countries, you should have noticed that these tones can vary
considerably, both in terms of frequency but also cadence. In North
America, there are standards for the public network, but once you've
left the public network & connect to a private PBX, you may encounter
something else entirely. Same for other countries, but with different
standards. Depending on where you're calling FROM, as well as TO,
you'll need to be able to reliably detect a variety of call progress
tones.

http://en.wikipedia.org/wiki/Precise_Tone_Plan
http://www.clare.com/home/pdfs.nsf/www/AN-CPTS-R1.pdf/$file/AN-CPTS-R1.pdf
http://www.3amsystems.com/wireline/tone-search.htm

JM

 

[John Fields]

On Tue, 2 Sep 2008 14:26:07 -0700 (PDT), lerameur <lerameur@yahoo.com>
wrote:

On Sep 2, 5:15 pm, John Fields <jfie...@austininstruments.com> wrote:
On Tue, 2 Sep 2008 12:16:36 -0700 (PDT), lerameur <leram...@yahoo.com
wrote:

Hello,

I am using a pic controller  for a dialer project. My goal is to dial
a number, when the receiving end picks up, then send some dtmf tone
for a few minutes.
Sounds simple, but I do not know how to tell my controller that the
receiving end has picked up or not. Right now I just let it ring for
10 seconds, and send my dial tone after that. I would like it to be
more 'intelligent' by knowing when the receiver has picked up so I can
send the dial tone (message),
thanks

---
If you're going to use the remote phone for remote control purposes
you could have it shake hands with the controller:

      LOCAL                           REMOTE

DIAL---------------------------->DETECT RING
WAIT FOR HANDSHAKE               GO OFF-HOOK
RX HANDSHAKE <------------------ TX DTMF HANDSHAKE TONES
                                 WAIT FOR DTMF DATA
TX DTMF DATA-------------------->RX DTMF DATA

JF

Yes but how is this handle in circuitry. I just realize that I cannot
use the same circuit with audio transformer as I did in DTMF to signal
out.

---
Of course you can.

If you're using a proper transformer, then DTMF is entirely within the
bandwidth of the transformer.
---

How should the voltage at the line while dialing?

---
If you're properly coupled to the phone line with a transformer, why
should you care?
---

and once the party has pick up the phone ?

---
I'm confused.

How about some detailed information regarding what you're trying to
do?

JF

 

[lerameur]

On Sep 3, 10:41 am, John Mianowski <spamf...@skytex.net> wrote:

On Sep 2, 2:16 pm, lerameur <leram...@yahoo.com> wrote:

Hello,

I am using a pic controller  for a dialer project. My goal is to dial
a number, when the receiving end picks up, then send some dtmf tone
for a few minutes.
Sounds simple, but I do not know how to tell my controller that the
receiving end has picked up or not. Right now I just let it ring for
10 seconds, and send my dial tone after that. I would like it to be
more 'intelligent' by knowing when the receiver has picked up so I can
send the dial tone (message),
thanks

K

That's always a problem for loop-start lines, which I presume is what
you have.  They're designed for calls placed by humans, to humans,
rather than machine-to-machine trunks.  There isn't any 100% positive
electrical signal, such as a voltage level, current flow, etc. that's
transmitted end-to-end & can alert a dumb machine to a distant-end
answer.

What's usually used to determine answer is call progress tone
detection.  Call progress tones are the various tones that alert a
human caller to the status of the call.  Common call progress tones
include dial tone, ring-back, busy, & reorder.  All of these tones
appear within the audio frequency band of the circuit, mostly as pairs
of frequencies.  If you've ever called to or from certain PBXes, or
various countries, you should have noticed that these tones can vary
considerably, both in terms of frequency but also cadence.  In North
America, there are standards for the public network, but once you've
left the public network & connect to a private PBX, you may encounter
something else entirely.  Same for other countries, but with different
standards.  Depending on where you're calling FROM, as well as TO,
you'll need to be able to reliably detect a variety of call progress
tones.

http://en.wikipedia.org/wiki/Precise_Tone_Planhttp://www.clare.com/home/pdfs.nsf/www/AN-CPTS-R1.pdf/$file/AN-CPTS-R...http://www.3amsystems.com/wireline/tone-search.htm

JM

I have been reading up on them, these are call progress IC .
They are now next to impossible to get. I guess now they do a DSP
version so they dont need this hardware.
Anybody whith an algorithm out there ?

K

 

[lerameur]

On Sep 3, 3:36 pm, John Fields <jfie...@austininstruments.com> wrote:

On Tue, 2 Sep 2008 14:26:07 -0700 (PDT), lerameur <leram...@yahoo.com
wrote:



On Sep 2, 5:15 pm, John Fields <jfie...@austininstruments.com> wrote:
On Tue, 2 Sep 2008 12:16:36 -0700 (PDT), lerameur <leram...@yahoo.com
wrote:

Hello,

I am using a pic controller  for a dialer project. My goal is to dial
a number, when the receiving end picks up, then send some dtmf tone
for a few minutes.
Sounds simple, but I do not know how to tell my controller that the
receiving end has picked up or not. Right now I just let it ring for
10 seconds, and send my dial tone after that. I would like it to be
more 'intelligent' by knowing when the receiver has picked up so I can
send the dial tone (message),
thanks

---
If you're going to use the remote phone for remote control purposes
you could have it shake hands with the controller:

      LOCAL                           REMOTE

DIAL---------------------------->DETECT RING
WAIT FOR HANDSHAKE               GO OFF-HOOK
RX HANDSHAKE <------------------ TX DTMF HANDSHAKE TONES
                                 WAIT FOR DTMF DATA
TX DTMF DATA-------------------->RX DTMF DATA

JF

Yes but how is this handle in circuitry. I just realize that I cannot
use the samecircuitwith audio transformer as I did in DTMF to signal
out.

---
Of course you can.

If you're using a proper transformer, then DTMF is entirely within the
bandwidth of the transformer.
---

How should the voltage at the line while dialing?

---
If you're properly coupled to the phone line with a transformer, why
should you care?
---

and once the party has pick up the phone ?

---
I'm confused.

well that was before I knew that Central office sends out different
frequency on the status the phone of the receiver.
I will look for those frequencies now.
440Hz and 480Hz means that is it ringing, if it stops, then I suppose
some pickup at the other end, Then I can program the controller to
send my signal.

K

 

[lerameur]

On Sep 4, 9:43 am, Charlie Siegrist <n...@this.time> wrote:

On Wed, 3 Sep 2008 12:50:16 -0700 (PDT), lerameur <leram...@yahoo.com
wrote:

well that was before I knew that Central office sends out different
frequency on the status the phone of the receiver.
I will look for those frequencies now.
440Hz and 480Hz means that is it ringing, if it stops, then I suppose
some pickup at the other end, Then I can program the controller to
send my signal.

And whose ears are you going to fill with DTMF?  If the remote end is
also an automated site under your control, a DTMF handshaking routine
can be set up, as has been pointed out to you.  It's been done before,
believe it or not.  If the other end is not an automated site under
your control, then you are going to very quickly become an extremely
annoying person.

Well lets say I am at work, and my alarm system goes off, it will
trigger the dialer. First, I will see on my phone that someone is
calling me from home from the call display. Then if I hear a
continuous dial tone for 20 seconds, then I will know my alarm is on.

K

 

[Ross Herbert]

On Thu, 4 Sep 2008 07:11:49 -0700 (PDT), lerameur <lerameur@yahoo.com> wrote:
:
:Well lets say I am at work, and my alarm system goes off, it will
:trigger the dialer. First, I will see on my phone that someone is
:calling me from home from the call display. Then if I hear a
:continuous dial tone for 20 seconds, then I will know my alarm is on.
:
:K


You've lost me....

Your alarm at home triggers and dials your work number. You see on your CLI
display at work that the calling number is your home. Then you hear 20 seconds
of dial tone so you will know your alarm is "ON"....??????? (scratches head in
wonderment).

BTW, don't you mean, "you will know your home alarm has been triggered"?

Where is the 20 seconds of dial tone coming from? And why dial tone?

I suggest you start out with something like this project and refine it if
necessary.
http://users.tpg.com.au/users/talking/DialAlarm-1-Page1.html

 

[Charlie Siegrist]

On Fri, 05 Sep 2008 02:02:12 GMT, Ross Herbert
<rherber1@bigpond.net.au> wrote:

On Thu, 4 Sep 2008 07:11:49 -0700 (PDT), lerameur <lerameur@yahoo.com> wrote:
:
:Well lets say I am at work, and my alarm system goes off, it will
:trigger the dialer. First, I will see on my phone that someone is
:calling me from home from the call display. Then if I hear a
:continuous dial tone for 20 seconds, then I will know my alarm is on.
:
:K


You've lost me....

Your alarm at home triggers and dials your work number. You see on your CLI
display at work that the calling number is your home. Then you hear 20 seconds
of dial tone so you will know your alarm is "ON"....??????? (scratches head in
wonderment).

BTW, don't you mean, "you will know your home alarm has been triggered"?

Where is the 20 seconds of dial tone coming from? And why dial tone?

I suggest you start out with something like this project and refine it if
necessary.
http://users.tpg.com.au/users/talking/DialAlarm-1-Page1.html

Haven't looked at your link yet, but this is an easy one. Since the
human is in control of the situation on the receive end, answer the
phone and press #99 or some other acknowledging code, and the
auto-dialer can respond in whatever way it's been programmed. A whole
series of DTMF communication may be programmed, depending on the
sophistication of the auto-dialer apparatus.

Of course, the assumption remains that the receiving human knows that
the alarm has triggered from the mere fact that home is calling, and
presumably is not the wife asking to have a loaf of bread or jar of
pickles picked up on the way home. Unless there is something
tangible that gives value to the receiver communicating with the
auto-dialer, there is no need for anything more than caller-ID at the
receiving end.

 

[Charlie Siegrist]

On Thu, 4 Sep 2008 07:11:49 -0700 (PDT), lerameur <lerameur@yahoo.com>
wrote:

Well lets say I am at work, and my alarm system goes off, it will
trigger the dialer. First, I will see on my phone that someone is
calling me from home from the call display. Then if I hear a
continuous dial tone for 20 seconds, then I will know my alarm is on.

OK, I found the other thread that you started about the PIC. It would
have been very helpful in this thread if you would have stated that
the auto-dial controller was very primitive and used pusle dialing.
This makes DTMF out of the question, although for some reason you
mentioned DTMF in your first post in this thread. What, exaclty, are
the capabilities of your auto-dialer? If you just want to answer the
phone and be hit with a tone, just warble 500 and 1000 Hz, you'll get
the message.

 

[Ross Herbert]

On Thu, 04 Sep 2008 19:28:15 -0700, Charlie Siegrist <none@this.time> wrote:

:On Fri, 05 Sep 2008 02:02:12 GMT, Ross Herbert
:<rherber1@bigpond.net.au> wrote:
:
:>On Thu, 4 Sep 2008 07:11:49 -0700 (PDT), lerameur <lerameur@yahoo.com> wrote:
:>:
:>:Well lets say I am at work, and my alarm system goes off, it will
:>:trigger the dialer. First, I will see on my phone that someone is
:>:calling me from home from the call display. Then if I hear a
:>:continuous dial tone for 20 seconds, then I will know my alarm is on.
:>:
:>:K
:>
:>
:>You've lost me....
:>
:>Your alarm at home triggers and dials your work number. You see on your CLI
:>display at work that the calling number is your home. Then you hear 20 seconds
:>of dial tone so you will know your alarm is "ON"....??????? (scratches head in
:>wonderment).
:>
:>BTW, don't you mean, "you will know your home alarm has been triggered"?
:>
:>Where is the 20 seconds of dial tone coming from? And why dial tone?
:>
:>I suggest you start out with something like this project and refine it if
:>necessary.
:>http://users.tpg.com.au/users/talking/DialAlarm-1-Page1.html
:
:Haven't looked at your link yet, but this is an easy one. Since the
:human is in control of the situation on the receive end, answer the
hone and press #99 or some other acknowledging code, and the
:auto-dialer can respond in whatever way it's been programmed. A whole
:series of DTMF communication may be programmed, depending on the
:sophistication of the auto-dialer apparatus.
:
:Of course, the assumption remains that the receiving human knows that
:the alarm has triggered from the mere fact that home is calling, and
resumably is not the wife asking to have a loaf of bread or jar of
ickles picked up on the way home. Unless there is something
:tangible that gives value to the receiver communicating with the
:auto-dialer, there is no need for anything more than caller-ID at the
:receiving end.


I know the human at the receive end controls the situation and that he can
respond to the call using dtmf. But when he does this why would the sending end
respond with dial tone? This would require the generation of 2 tones which are
not part of the dtmf frequency plan. Ok, not hard to do in software, but it
seems unneccesary. Why not respond with one of the standard dtmf tones instead
of dial tone?

Out here dial tone is 400Hz + 425Hz afaik.

 

[Charlie Siegrist]

On Fri, 05 Sep 2008 03:01:36 GMT, Ross Herbert
<rherber1@bigpond.net.au> wrote:

<me>

:Of course, the assumption remains that the receiving human knows that
:the alarm has triggered from the mere fact that home is calling, and
resumably is not the wife asking to have a loaf of bread or jar of
ickles picked up on the way home. Unless there is something
:tangible that gives value to the receiver communicating with the
:auto-dialer, there is no need for anything more than caller-ID at the
:receiving end.


I know the human at the receive end controls the situation and that he can
respond to the call using dtmf. But when he does this why would the sending end
respond with dial tone? This would require the generation of 2 tones which are
not part of the dtmf frequency plan. Ok, not hard to do in software, but it
seems unneccesary. Why not respond with one of the standard dtmf tones instead
of dial tone?

I agree that sending dial-tone is odd. I think the OP is just
throwing out chum to see what bites. If you read the info on the link
he posted here:

Message-ID:
<7084b761-d5fd-4b06-96ca-45286c16116a@d77g2000hsb.googlegroups.com>

it states that the auto-dialer will send a 300Hz tone for 30 seconds
after placing the call. I think OP wants to expand on the idea a
little, and is just guessing that sending dial tone as opposed to
300Hz is a better idea. I don't think his auto-dialer is capable of
DTMF, after reading the message referenced above. Much is left
unexplained about the project he is pursuing.

 

[Charlie Siegrist]

On Wed, 3 Sep 2008 12:50:16 -0700 (PDT), lerameur <lerameur@yahoo.com>
wrote:

well that was before I knew that Central office sends out different
frequency on the status the phone of the receiver.
I will look for those frequencies now.
440Hz and 480Hz means that is it ringing, if it stops, then I suppose
some pickup at the other end, Then I can program the controller to
send my signal.

And whose ears are you going to fill with DTMF? If the remote end is
also an automated site under your control, a DTMF handshaking routine
can be set up, as has been pointed out to you. It's been done before,
believe it or not. If the other end is not an automated site under
your control, then you are going to very quickly become an extremely
annoying person.

 

[lerameur]

On Sep 4, 11:01 pm, Ross Herbert <rherb...@bigpond.net.au> wrote:

On Thu, 04 Sep 2008 19:28:15 -0700, Charlie Siegrist <n...@this.time> wrote:

:On Fri, 05 Sep 2008 02:02:12 GMT, Ross Herbert:<rherb...@bigpond.net.au> wrote:

:
:>On Thu, 4 Sep 2008 07:11:49 -0700 (PDT), lerameur <leram...@yahoo.com> wrote:
:>:
:>:Well lets say I am at work, and my alarm system goes off, it will
:>:trigger the dialer. First, I will see on my phone that someone is
:>:calling me from home from the call display. Then if I hear a
:>:continuous dial tone for 20 seconds, then I will know my alarm is on.
:>:
:>:K
:
:
:>You've lost me....
:
:>Your alarm at home triggers and dials your work number. You see on your CLI
:>display at work that the calling number is your home. Then you hear 20 seconds
:>of dial tone so you will know your alarm is "ON"....??????? (scratches head in
:>wonderment).
:
:>BTW, don't you mean, "you will know your home alarm has been triggered"?
:
:>Where is the 20 seconds of dial tone coming from? And why dial tone?
:
:>I suggest you start out with something like this project and refine it if
:>necessary.
:>http://users.tpg.com.au/users/talking/DialAlarm-1-Page1.html
:
:Haven't looked at your link yet, but this is an easy one.  Since the
:human is in control of the situation on the receive end, answer the
hone and press #99 or some other acknowledging code, and the
:auto-dialer can respond in whatever way it's been programmed.  A whole
:series of DTMF communication may be programmed, depending on the
:sophistication of the auto-dialer apparatus.
:
:Of course, the assumption remains that the receiving human knows that
:the alarm has triggered from the mere fact that home is calling, and
resumably is not the wife asking to have a loaf of bread or jar of
ickles picked up on the way home.   Unless there is something
:tangible that gives value to the receiver communicating with the
:auto-dialer, there is no need for anything more than caller-ID at the
:receiving end.

I know the human at the receive end controls the situation and that he can
respond to the call using dtmf. But when he does this why would the sending end
respond with dial tone? This would require the generation of 2 tones which are
not part of the dtmf frequency plan.  Ok, not hard to do in software, but it
seems unneccesary. Why not respond with one of the standard dtmf tones instead
of dial tone?

Out here dial tone is 400Hz + 425Hz afaik.

After reading on the subject I realize that the Central office sends
out signals about state of the connection (ringing, busy). I am going
to get a transceiver chip so I can dial out and get the signals, I
think the MTC888 should be good for this.
K